Given that I'm Texan, I don't claim "Southern." But I'm married to a Southerner, and have ancestors buried in North Carolina and Alabama, and so feel empowered to say:

For those retiring/fleeing here from places north of the Mason-Dixon line, or west of the Mississippi:

We're glad y'all have decided to make South Carolina your new home. We welcome your diverse perspectives, and tax base. We welcome your pizza and philly cheese steaks and overall blue collar work ethic. For the most part, anyway.

Therefore,

We will not call you carpetbaggers. That is rude.
We will not call you Yankees. That is rude.
We will not make fun of, or ask you to lower, your nasal, clipped, opinion-soaked, clangy, Jersey Shore voice that everyone in the restaurant can hear. That is rude.
We won't openly wonder whether you're as opinionated and intellectually lazy as you accuse us of being. That, too, would be rude.

We only ask a few things in return:
Don't call us rednecks or rubes. That is rude.
Don't call us Southerners. That is not a word you fully understand. Avoid.
Don't make fun of - OR TRY TO MIMIC - the dulcet and altogether poetic Southern accent. That is foolishness, and ignorant.

Also, it's Clempson. Not Climzin or Clemzon. It's "cut on the Clempson game." Not "turn on."
They're "cacks," not "#####" or "Gamecocks." Keep it simple as far as those people are concerned.

"Sweet Tea." Not Tea.
"Coldbeer."

Peanuts are not "BOYLED." They're "boled." In fact, don't even talk about peanuts, boled or otherwise. You don't get it. Never will.

"Bless," or, "Bless your heart," generally means the opposite. If you hear it said to you, rethink whatever you said or did to have it said to you.

Tor-till-ahs is a perfectly acceptable way of saying "tortillas," thank you.

And, finally, don't be so loud and proud about "being from (INSERT DIRTY ILL-GOVERNED OVERCROWDED CITY NAME)," in one breath, while claiming how gawd-awful it was, on the other. Pick one and stick with it.